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You CAN do this at home -if you like!

Old 05-13-2013, 08:37 PM
  #1  
quorneng
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Default You CAN do this at home -if you like!

In the usual IC versus Electric banter it was claimed that IC did not mind getting wet where as electric did.

I pointed out that a brushless motor was quite happy running under water as not only are the windings insulated but the electrical conductivity of water at low voltages (<20V) is quite low.

I thought I had better prove it!
https://vimeo.com/66087990
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Old 05-13-2013, 09:05 PM
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flydiver
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Speed Control hates getting soaked though. Probably not an issue with rain but a full dunking is not such a great deal.
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Old 05-13-2013, 09:28 PM
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road king 97
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I use to break my brushed motors under water it was good to get the shavings out while breaking the brushes in. joe
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Old 05-14-2013, 03:55 AM
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kyleservicetech
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Originally Posted by flydiver View Post
Speed Control hates getting soaked though. Probably not an issue with rain but a full dunking is not such a great deal.
Yeah
I had (Note Had!) an ESC in a foamie jet last winter where the air intake for the fan was on the bottom of the model.

Two landings in the snow, the second one filled the entire fan intake full of snow. You guessed it. The third flight, the snow that was in the ESC melted when the ESC warmed up, and good by ESC. That electric model made a trail of smoke before it landed.

That ESC actually melted a hole clear through the foam. Got another ESC, but have not flown it yet.

As for running a brushless motor under water, I'd not try it. Those brushless motor ball bearings are pretty heavily loaded, and turn over at high RPM. Methinks washing out the little lube that is present in these ball bearings would not be very good.
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Old 05-13-2013, 09:56 PM
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rcers
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Will it technically run underwater - yes, is it happy - no. The metal parts rust, the bearings really don't like it either.

Mike
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Old 05-14-2013, 12:09 AM
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road king 97
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Originally Posted by rcers View Post
Will it technically run underwater - yes, is it happy - no. The metal parts rust, the bearings really don't like it either.

Mike
Your supose to oil them after breaking brushed motors under water Mike. Its how many of us did it back in the day and all mine still turn fine. joe
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Old 05-14-2013, 01:55 AM
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rcers
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Originally Posted by road king 97 View Post
Your supose to oil them after breaking brushed motors under water Mike. Its how many of us did it back in the day and all mine still turn fine. joe
Yes I have broken in a s400 or two or ten. First you used WD-40 to get rid of the water it actually does work well doing that. Then a nice light machine oil.

Since brushless motors don't need to have the brushes broken in - I guess this was just a fun test.

Mike
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Old 05-13-2013, 10:54 PM
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fhhuber
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similarly the glow or gasoline engines can rust when exposed to water...

You can protect your equipment from water. Either way you have a radio system that isn't going to lake getting wet if you don't "waterproof" it. The same waterproofing works for the ESC and battery of an e-power aircraft.
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Old 05-14-2013, 02:59 AM
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I don't recommend running the brushless motor under water with the prop (intended for flight) still on.
You'd be very likely to blow the ESC due to the higher load.

I can see nothing wrong with mounting a brushless motor under a boat with an appropriate prop and using the water to cool it. Pull from the water and run it (virtually no prop load out of the water) to warm it up to dry out.
There are now some trolling motors that do that.
Better to have a motor that is made for the purpose... but it would work. Just with expected shorter bearing life due to water driving the oil out. (but water would lube the bearings some...)
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Old 05-14-2013, 03:21 AM
  #10  
starcad
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I remember doing it years back with brushed motors and then oiling the heck out of the bearings. Thought it crazy at first and then when I saw the results I was convinced.
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Old 05-14-2013, 03:37 AM
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Glacier Girl
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At the China model show they had, servos/esc's/rx's operating under water.
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